Cardiac transseptal instruments, assemblies, and method of use of the same

ABSTRACT

A needle or stylet has a tip contour with a reverse back bevel curved toward the longitudinal axis of the needle or stylet. The needle has a flexible intermediate portion and/or a two-part construction in which a distal portion of the needle to crimped onto a proximal portion of the needle. The needle or a stylet is combined with a spring mechanism in the hub of the needle or stylet assembly. The spring mechanism positions the tip of the needle or stylet in a middle position extending from the distal end of the assembly, allows the needle or stylet to be moved into a spring loaded fully retracted configuration within the assembly as the septal wall is tented, and then releasing the spring loaded needle or stylet as the needle or stylet penetrates the septal wall. A method of using a needle or stylet with a spring mechanism is included.

BACKGROUND

This application claims priority to, and the benefit of the earlierfiling date of US non-provisional patent application entitled“IMPROVEMENTS IN CARDIAC TRANSSEPTAL INSTRUMENTS, ASSEMBLIES, AND METHODOF USE OF THE SAME”, filed on Jan. 21, 2020, Ser. No. 16/748,610,pursuant to 35 USC 120, the contents of all of which are incorporatedherein by reference.

FIELD OF THE TECHNOLOGY

The invention relates to the field of transseptal puncture apparatus,assemblies, and methods, such as included within International ClassesA61B 17/34; A61M 25/01; A61M 25/09; A61B 17/00; A61B 17/06; A61B 17/22;A61M 5/178; and A61M 5/32.

DESCRIPTION OF THE PRIOR ART

Transseptal puncture needles and transseptal puncture needle assembliesare well known, and more specifically, curved transseptal punctureneedles and needle assemblies that facilitate insertion through curvedtransseptal introducers to minimize skiving the interior lumen of theintroducer have been developed. One example of such a needle assembly isdisclosed by Gurusamy, U.S. Pat. No. 7,635,353. The needle tip is shownin FIG. 29 of that patent and is defined by a needle tip with one ofseveral different complex configurations, called a tangential backbevel, a reverse tangential back bevel, or a conical reverse bevel.Another example is disclosed by Bednarek, U.S. Pat. No. 8,114,110. Theneedle tip as shown in FIGS. 16-19 provide an “extra sharp” version ofthe Gurusamy needle tip. The configurations contemplate compound orcomplex multifaceted surfaces and are difficult to manufactureconsistently in needle tips without undertaking costly manufacturingprocesses. What is needed is a design that can readily and inexpensivelybe manufactured with high precision in the material specificationsrelevant to puncture capability and antiskiving performance.

Moreover, in addition to a needle assembly which does not skive theinterior lumen of the introducer, it is desirable that the needle cancross or penetrate the septal wall without undue resistance or tentingof the septal wall. The fibrousity and thickness of the septal wall mayvary considerably from one patient to another, and it is desirable thatthe transseptal needle assembly be able to easily or controllablypuncture the septal wall regardless of patient variability. Hence, whatis needed is some kind of design which allows for ease of puncture ofseptal walls of varying fibrousity or thickness, or which design allowsfor different degrees of sharpness of the needle tip.

One of the common considerations in transseptal needle design is thesafety of the use of the needle assembly during the penetration of theseptal wall. If after the needle punctures the septal wall, and it has aconfiguration that may damage or puncture the opposing wall of the leftatrium, undue hazard may be associated with the design. Moreover, it theneedle encounters enough resistance to puncturing the septal wall suchthat the septal wall is tented by the advancing introducer or needle,the septal wall may suddenly rebound when puncture is achieved with theresult that the position of the needle tip is briefly uncontrolled andends in an unintended position or causes cardiac damage. In addition tocost and ease of manufacture and good puncture performance,controllability of the puncture and the assumption of an atraumaticconfiguration of the needle tip once puncture is achieved is desirableas well.

What is needed is some kind of a design that does not skive theintroducer, that is inexpensive and which can be consistently bemanufactured with high precision, which has high puncture performance,and which is atraumatic once puncture is achieved.

BRIEF SUMMARY

The current invention provides a hollow needle assembly for atransseptal cardiac needle. The hollow needle assembly includes a distalportion, a proximal portion, and a spring mechanism that coupled to thehollow needle assembly such that the spring mechanism is loaded when thehollow needle assembly is advanced against a predetermined position on aseptal wall. The spring mechanism is unloaded after the transseptalcardiac needle penetrates the septal wall allowing the distal portion ofthe transseptal cardiac needle to extend unsupported and thereby assumean atraumatic configuration. The distal portion of the transseptalcardiac needle is comprised of material that is more flexible relativeto the proximal portion.

In one embodiment, the distal portion of the transseptal cardiac needleincludes a spiral structure which provides it with increased flexibilityas compared to the proximal portion. The distal portion of thetransseptal cardiac needle includes a defining wall and where the spiralstructure comprises thinning the defining wall of the distal portion ina spiral pattern. Alternatively, the distal portion of the transseptalcardiac needle is comprised of a spiral wrap. Specifically, the distalportion of the transseptal cardiac needle may have a predetermined curvedefined therein.

In another embodiment, the distal portion of the transseptal cardiacneedle includes a defining wall and where the structure comprisesthinning the defining wall of the distal portion.

In a further embodiment, the distal portion of the transseptal cardiacneedle includes an inherently flexible material. Specifically, theinherently flexible material may be nitinol.

In another embodiment, the hollow needle assembly for a transseptalcardiac needle also includes a stylet coupled to the spring mechanismsuch that the spring mechanism is loaded when the stylet is advancedagainst a predetermined position on a septal wall, and where the springmechanism is unloaded after the transseptal cardiac needle penetratesthe septal wall allowing the distal portion of the transseptal cardiacneedle to extend unsupported and thereby assume an atraumaticconfiguration.

In a further embodiment, the transseptal cardiac needle includes a birdbeak tip, where the bird beak tip itself includes an inner surface andan outer surface. More specifically, the bird beak tip has alongitudinal axis and a leading edge of the bird beak tip, where theleading edge of the bird beak tip is located at and adjacent to thedistal end of the inner and outer surfaces. The inner surface of thehollow transseptal cardiac needle defines an opening of the bird beaktip and the distal end of the bird beak tip is curved relative to thelongitudinal axis of the hollow transseptal cardiac needle into theopening of the bird beak tip.

In another embodiment, the stylet includes a distal portion and aproximal portion, where the distal portion is comprised of material thatis more flexible relative to the proximal portion.

In an additional embodiment the transseptal cardiac needle includes atip which in turn includes an inner surface of the needle, an outersurface of the needle, where the inner and outer surfaces of the needlehave a common longitudinal axis, a bevel provided on a distal end of theneedle to define a face of the needle, and a pair of opposing sidebevels defined into a distal end of the face of the needle, the sidebevels intersecting at the distal end of the needle to define the needletip. The distal end of the needle and the needle tip bends toward thelongitudinal axis of the needle.

The current invention also provides a method of using a spring mechanismcoupled to an elongate stylet or needle for a transseptal cardiacprocedure. The method includes providing a stylet or needle comprising adistal portion and a proximal portion, where the distal portion isflexible relative to the proximal portion, disposing the stylet orneedle into an atrium in a heart oriented toward a selected positionagainst a septal wall, the stylet or needle being coupled to the springmechanism, and then advancing the stylet or needle against the selectedposition on the septal wall while tenting the septal wall and whilespring loading the spring mechanism. Next, the spring mechanism isautomatically unloaded as the stylet or needle penetrates the septalwall allowing the stylet or needle to extend unsupported into anopposing atrium and to assume an atraumatic configuration.

In one particular embodiment, providing the stylet or needle comprisinga distal portion and a proximal portion includes providing the distalportion with a spiral structure.

In a related embodiment, providing the stylet or needle comprising adistal portion and a proximal portion includes providing the distalportion with a spiral wrap.

In a further embodiment, providing the distal portion with a spiralstructure includes thinning a defining wall of the distal portion in aspiral pattern.

In one embodiment, providing the stylet or needle comprising a distalportion and a proximal portion comprises providing a distal portion thatis comprised of an inherently flexible material. Specifically, thedistal portion may be comprised of nitinol.

In an additional embodiment, the method also includes locking the springmechanism so that the stylet is fixed in position relative to the needleand serves to atraumatically prevent advancement of the needle intoheart tissue.

In another embodiment, the method also includes emitting a visual,audible, or tactile response from the spring mechanism to indicate whenthe stylet or needle is tenting the septal wall and/or when the needlehas perforated the septal wall.

While the apparatus and method has or will be described for the sake ofgrammatical fluidity with functional explanations, it is to be expresslyunderstood that the claims, unless expressly formulated under 35 USC112, are not to be construed as necessarily limited in any way by theconstruction of “means” or “steps” limitations, but are to be accordedthe full scope of the meaning and equivalents of the definition providedby the claims under the judicial doctrine of equivalents, and in thecase where the claims are expressly formulated under 35 USC 112 are tobe accorded full statutory equivalents under 35 USC 112. The disclosurecan be better visualized by turning now to the following drawingswherein like elements are referenced by like numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a side perspective view of a prior art needle tip having astandard B-bevel needle tip.

FIG. 1 b is a side perspective view of a needle tip having a reverseback bevel which is contoured toward the opposing side of the needle tipand is referenced herein as a “bird's beak” needle tip.

FIG. 2 a is a side elevational view of a prior art B-bevel needle tip ofFIG. 1 a.

FIG. 2 b is a top elevational view of the needle tip of FIG. 1 a.

FIG. 2 c is a side perspective view of the needle tip of FIG. 1 a

FIG. 2 d is a top perspective view of the needle tip of FIG. 1 a

FIG. 3 a is a side perspective view of the needle tip of FIG. 1 b.

FIG. 3 b is a top elevational view of the needle tip of FIG. 1 b.

FIG. 3 c is a side elevational view of the needle tip of FIG. 1 b

FIG. 4 is an overall side elevational view of the curved transseptalneedle assembly of the improved embodiments.

FIG. 5 is an enlarged longitudinal cross sectional view of the distalportion of the needle assembly of FIG. 4

FIG. 6 a is a side cross sectional view of the distal portion oftransseptal puncture device depicted in FIG. 1 a being inserted into acurved transseptal dilator.

FIG. 6 b is a side cross sectional view of the distal portion of acurved transseptal puncture device having a “bird beak” tipconfiguration depicted in FIG. 1 b being inserted into a curvedtransseptal dilator.

FIG. 7 is an overall side view of the transseptal puncture device withtwo-piece design with the distal portion shown in side cross sectionalview.

FIG. 8 a is a side cross sectional view of a blunt needle tip.

FIG. 8 b is a side perspective view of a blunt needle tip.

FIG. 8 c is a three quarter perspective view of a blunt needle tip.

FIG. 9 a is a three quarter perspective view of a conventional backbeveled needle tip such as shown in FIG. 29 of Gurusamy et.al., U.S.Pat. No. 7,635,353 incorporated herein by reference.

FIG. 9 b is a side perspective view of a conventional back beveledneedle tip such as shown in FIG. 29 of Gurusamy et.al., U.S. Pat. No.7,635,353.

FIG. 9 c is a top perspective view of a conventional back beveled needletip such as shown in FIG. 29 of Gurusamy et.al., U.S. Pat. No.7,635,353.

FIG. 9 d is a side elevational view of a conventional back beveledneedle tip such as shown in FIG. 29 of Gurusamy et.al., U.S. Pat. No.7,635,353.

FIG. 10 is a side view of the distal portion of a transseptal puncturedevice embodiment wherein the intermediate portion of the needle isprovided with flexible properties.

FIG. 11 a is a side cross sectional view of the distal portion of anembodiment wherein an intermediate portion of the needle is constructedwith a predetermined flexibility.

FIG. 11 b is an enlarged side cross sectional view of the distal portionof the embodiment of FIG. 11 a.

FIG. 11 c is an enlarged perspective view of the distal portion of theembodiment of FIG. 11 a.

FIG. 12 is a side elevational view of an embodiment wherein the distalportion of the needle is constructed with a predetermined flexibility.

FIG. 13 is a side view of the distal portion of an embodiment of atransseptal puncture device similar to FIG. 12 , wherein the distal tip,not the intermediate portion, is manufactured or formed from a materialsuch that it is more likely to bend than the proximal portion.

FIG. 14 is a side elevational view of the distal portion of anembodiment similar to the embodiment of FIG. 13 with the spiral tipsubstantially lengthened as compared to the J bend of FIG. 13 .

FIG. 15 a is a side elevational view of the distal portion of anembodiment in which the distal portion of the needle is fabricated witha ribbon-spiral structure to give it flexibility without loss ofcolumnar strength when confined within the introducer.

FIG. 15 b is a side perspective view of the distal portion of the needleof the embodiment of FIG. 15 a.

FIG. 16 is a side elevational view of a sharp needle and spring styletassembly.

FIG. 17 is a side view of an assembly including a stylet and bird beaktipped needle.

FIG. 17 a is an enlarged view of distal end of the bird beak tippedneedle and stylet of FIG. 17 with the stylet tip extending from thedistal end of the blunt tipped needle, but with a reduced diameterportion of the stylet retained in the needle where its columnar strengthis maintained.

FIG. 17 b is an enlarged view of distal end of the bird beak tippedneedle and stylet of FIG. 17 with the stylet tip fully retracted withinthe needle.

FIG. 17 c is an enlarged view of distal end of the bird beak tippedneedle and stylet of FIG. 17 with the stylet tip fully extended from theneedle.

FIG. 18 is a side cross sectional view of a spring mechanism coupled tothe stylet of FIG. 17-17 c,

FIG. 19 is a side cross sectional view of another embodiment of thespring mechanism incorporating a lockable slider coupled to the stylet.

FIG. 20 is a side plan view of another embodiment of the hub assemblyand spring mechanism coupled to a stylet.

FIG. 21 is a side plan view of yet another embodiment of the hubassembly and spring mechanism coupled to a stylet.

FIG. 22 is a side plan view of still yet another embodiment of the hubassembly and spring mechanism coupled to a stylet.

FIG. 23 is a side plan view of another embodiment of the hub assemblyand spring mechanism coupled to a stylet.

FIG. 24 is a side plan view of yet another embodiment of the hubassembly and spring mechanism coupled to a stylet.

FIG. 25 is a diagrammatic cross sectional view of a heart in which anatrial transseptal procedure is being performed using a bird's beaktipped needle and stylet.

FIG. 26 is a diagrammatic cross sectional view of a heart in which anatrial transseptal procedure is being performed using a blunt tippedneedle and sharp inner stylet.

FIGS. 27 a-27 c are top plan, side plan and perspective viewsrespectively of one embodiment of the prior art Gurusamy needle tipshown in U.S. Pat. No. 8,114,110.

FIGS. 28 a-28 d are top plan, side plan, bottom plan view andperspective views respectively of another embodiment with a back bevelof the prior art Gurusamy needle tip shown in U.S. Pat. No. 8,114,110.

FIG. 29 a is an enlarged side cross sectional view of the curvedtransseptal puncture device with prior art configuration inserted into atransseptal introducer.

FIG. 29 b is an enlarged cross sectional view of the curved transseptalpuncture device with the novel configuration of the bird's beak.

FIG. 30 is a side plan view of a sharpened or hypodermic needle showinga series of steps wherein the tip of the needle is formed into apredetermined bird's beak with a specifically defined tip offset and tipoffset length.

The disclosure and its various embodiments can now be better understoodby turning to the following detailed description of the preferredembodiments which are presented as illustrated examples of theembodiments defined in the claims. It is expressly understood that theembodiments as defined by the claims may be broader than the illustratedembodiments described below.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 a depicts a needle tip 10 having a prior art configuration with aB-bevel configuration, comprising a primary bevel 12 of approximately 18degrees off the vertical, I, left and right tangential bevels 14defining tip 16. The needle tip 10 includes the puncture tip leadingedge 16 and a wedge surface defined by bevel 12, which in the views ofFIGS. 2 b and 2 d can be seen to comprise two disconnected surfacesegments. The defining tip 16 is approximately radially aligned with thecutting or leading edge 17 at the inner diameter of needle tip 10defined by the primary bevel 12, so that the bird's beak needle 10 isnoncoring. FIG. 1 b depicts a needle tip 10 having the “bird beak”configuration, comprising a tangential back bevel configuration havingsome elements in common with the design of FIG. 1 a , but wherein aconventional A-Bevel, B-Bevel, or C-Bevel puncture tip has been bentinward or toward the opposing side of the needle tip 10 to provide acontoured surface 22. The needle exhibits a sharp pointed tip that iscurved towards the opening of the hollow needle creating an offset ofthe pointed tip from the outer surface of the hollow needle and anoffset of the pointed tip from the inner surface of the hollow needle.An A-Bevel puncture tip typically has a primary bevel angle of 12degrees from vertical, a B-Bevel puncture tip typically has a primarybevel angle of 18 degrees from vertical, and a C-Bevel puncture tiptypically has a primary bevel angle of 30 degrees from vertical asdefined in detail in the Federal Specification GG-N-196, now obsolete.Similar needle tip designs can be found in ISO 7864. As the primarybevel angle is lowered, the inherent puncture force is lowered. Table 1provides a comparison of puncture forces for various embodimentsnormalized to the puncture force of a standard transseptal needlecomparing the “bird beak” offset pointed tip configuration with ab-bevel as compared to a standard and “extra sharp” commerciallyavailable transseptal needle tip. Details of two embodiments of theextra sharp tip are better shown in FIGS. 27 a-27 c and in FIGS. 28 a-28d for a tip with a back bevel as shown in U.S. Pat. No. 8,114,110. Thisembodiment decreases the risk of scraping along the inner surface of theintroducer (not shown) into which the needle tip 10 is inserted, whilemaintaining a sharp distal puncture tip 20 to allow for easy puncturethrough tough and/or fibrous septa of the heart.

TABLE 1 Insertion Force Description (percentage) Prior art standardtransseptal (FIG. 9a) 100%  Prior art extra sharp transseptal (FIGS. 62%27a -28d). Bird Beak transseptal (FIG. 1b) 28%

In the cannula-insert assembly 24 of FIG. 4 and as better seen in theenlarged partial view of FIG. 5 , a cannula 26 is used inside a dilator40 (FIG. 6 a ) to shape the curved transseptal introducer 32 (FIG. 6 a )and provide it with columnar support. At its proximal end the cannula 26is fit into a hub and handle assembly 30, which is used to direct theinsertion of the cannula-insert assembly 24 into an introducer 32 shownin FIGS. 6 a and 6 b . At the distal end of the cannula 26, an insert 34is fed into the inner lumen of cannula 26. The distal end of insert 34is provided with a configuration as shown in FIG. 4 and extends beyondthe cannula's distal end to act as the puncture leading edge. Insert 34integrally includes the tip 16 or 20 of needle 10, or the tip 16 or 20may be a two-part construction with insert 34. The insert 34 is fixed inplace within the cannula 26 lumen by means of a crimped area 36, whereinthe cannula wall has been compressed inward with small detents on allsides such that small folds or ridges form to grip the outer wall of theinsert 34. Crimping is an economic, quick and reliable means of joiningtubular elements, particularly if made of different materials. In thismanner, an expensive distal element for needle 10 can be joined to aless expensive insert 34, or a less expensive cannula 26, therebymaterially simplifying and reducing the cost of the cannula-insertassembly 24 The cannula-insert assembly 24 is then shaped with a distalcurvature to fit the desired anatomy in the heart. The “bird beak”embodiment of FIG. 3 c is also easily constructed by starting with abeveled needle tip with the desired primary bevel angle and “bending”the needle tip inward towards the bevel heel. This operation requiresprecision tooling or a die as the amount of bend as discussed inconnection with FIG. 30 below is critical to maintain low punctureforces while preventing skiving of the introducer.

FIG. 30 is a side plan view of a sharpened or hypodermic needle showinga series of steps wherein the tip of the needle is formed into apredetermined bird's beak with a specifically defined tip offset and tipoffset length. Needle tip 10 is formed in a hollow needle with an outerdiameter 11 as best shown in the rightmost depiction in FIG. 30 . A die,not shown, defining a predetermined curvature is disposed on needle 10and by forming a selected one of predetermined curvatures on needle 10as suggested by the series of side views of needle 10 in FIG. 10 movingfrom right to left. Ultimately, a predetermined shape or curvature ofneedle 10 is formed having a puncture tip 20 and contoured surface 22.The tip offset 21 from the forward most extension of puncture tip 20 tothe back surface of needle 10 is in one embodiment defined to be aminimum of 0.010 inch (0.254 mm) and a maximum of one half the outerdiameter 11 of needle 10. The tip offset 23 is defined as the distancein vertical projection from the base of contoured surface 22 where itjust begins to curve to the puncture tip 20.

The operation and advantages of the needle tip 10 of FIG. 30 isillustrated by comparison of FIGS. 29 a and 29 b . FIG. 29 a is anenlarged side cross sectional view of the curved transseptal puncturedevice 10 of FIG. 1 a with prior art configuration inserted into atransseptal introducer. The straight sharp tip 16 is shown skiving theinner wall 41 of the dilator 40. FIG. 29 b is an enlarged crosssectional view of the curved transseptal puncture device 10 of FIG. 1 bwith the configuration of the bird's beak. The tip 20 is bent inwardrelative to the longitudinal axis of the needle 10, thereby offsettingthe tip 20 from the inner wall 41 of the dilator 40. This bend decreasesthe chance of skiving because the tip 20 does not catch on the dilator40.

FIG. 6 a is a side cross sectional view of the distal portion of acurved transseptal puncture device 38 having the prior art tipconfiguration depicted in FIG. 1 a being inserted into a curvedtransseptal introducer 32, comprised of a sheath (not shown) and ahollow dilator 42. The dilator 42 has a convex side 44 and a concaveside 46 as well as a defined curvature that is meant to match thecurvature of the anatomy in which it is used. As the needle 10 isadvanced through the dilator lumen 48, a first side of the needle movesalong the convex side 44 of the dilator 42. When the needle 10 isadvanced into the curvature of the dilator 42, the puncture tip 16leading edge of the prior art configuration may scrape along the innersurface of the convex side 46 of the dilator 42. As a result, thetransseptal puncture device 38 is difficult to insert through thedilator 42 and is capable of shaving dilator material (skiving) from itsinner surface. This material may then obstruct the lumen 48 of thedilator 42 or of the needle 10 or may dislodge into the patient.

FIG. 6 b is a side cross sectional view of the distal portion of acurved transseptal puncture device 38 having the “bird beak” tipconfiguration depicted in FIG. 1 b being inserted into a curvedtransseptal dilator 42 in the same manner as FIG. 6 a above and asbetter depicted in FIGS. 29 b and 30 below. Unlike the prior artversion, this tip configuration is curved inward, so when the needle 10is advanced through the lumen 48 of the dilator 42, the puncture tip 20leading edge does not move along the inner surface of the convex side 44of the dilator 42. The rounded surface of the back bevel behind andproximal from tip 20 resulting from the bending the tip 20 upward ortoward the opposing side of needle 10 causes the puncture tip 20 leadingedge to move unobstructed through the lumen 48 of the dilator 42 withoutcontacting the inner surface of the dilator 42. This eases theadvancement of the transseptal puncture device 38 and reduces the riskof shaving dilator material (skiving) which could enter into thepatient.

The blunt end cannula 26 used inside the dilator 42 imparts a definedshape to the curved transseptal introducer 32 and provides it withcolumnar support. At its proximal end the cannula 26 is fitted into ahub and handle assembly 30, which is used to direct the insertion of thecannula-insert assembly 24 into the curved transseptal introducer 32. Atthe distal end of the cannula 26, an insert 34 is fed into its innerlumen 28. The distal end of this insert 34 is imparted with theconfiguration as discussed in FIG. 1 a or 1 b and extends beyond thecannula distal end to act as the puncture leading edge. As stated above,the insert 34 is fixed in place within the cannula inner lumen 28 bymeans of a crimped area 36, wherein the cannula wall has been compressedinward on all sides such that small folds or ridges form to grip theouter wall of the insert 34. While the illustrated embodiment utilizes acrimp as the structure of connection of insert 34 as the most economicaland practical means of connection, it is also possible to join theinsert 34 by gluing, soldering, welding, swaging or other equivalentmeans. The cannula-insert assembly is then imparted with a distalcurvature to fit the anatomy in which the assembly will be used. Thisembodiment is similar to prior embodiments, but the two-piece crimpingmethod of assembly significantly reduces manufacturing costs.

In another embodiment, the distal end of insert 34 in FIG. 7 or two-partcrimped needle 10 is provided with a blunt tip configuration as shown inFIGS. 8 a-8 c . There is no sharp tip or puncture edge, but the tip 52may be imparted with a chamfer, fillet, radius, or other feature thatallows it to pass smoothly through the lumen 48 of the dilator 42 (FIG.6 a ). This transseptal puncture device 38 embodiment is intended to beused with a sharp tip guidewire 50 (not shown), or sharp tipped stylet51 (not shown). The septum may be tented as is the conventional medicalpractice, by using the tip of the blunt dilator 42 and/or the tip 52 ofthe blunt needle 10. The sharp tip guidewire 50 is then used to puncturethe septum. The sharp tip guidewire 50 and blunt needle 10 may then beadvanced into the left atrium. This embodiment is advantageous because asharp needle tip is not needed when utilizing a sharp tip guidewire 50.The blunt tip needle 10 provides columnar support to the guidewire 50while reducing the chance of skiving the dilator 42 during insertion,and because it is far less sharp than conventional penetrating needletips, it poses a reduced risk of puncturing the left atrial free wall.

Not only may the blunt tip 52 of FIGS. 8 a-8 c may be included in thetwo-part needle construction, but any other known needle tipconfiguration, may be used with the disclosed crimped two-part needleconstruction.

FIG. 10 is a side view of the distal portion of an embodiment of atransseptal puncture device 38 wherein the intermediate portion 56 ofthe needle 10 is designed with a predetermined flexibility. The proximalportion 58 of the needle 10 is rigid to provide column strength as it ispassed through the introducer 32. The intermediate portion 56 of theneedle 10 is manufactured or formed from a material such that it is morelikely to bend than the proximal portion 58. For example, the immediateportion 56 may be composed of nitinol and annealed at 500 degreesCentigrade for 10 minutes to relieve stress in otherwise super-elasticnitinol wire in an as-drawn condition. Alternatively, the material maybe made from a softer material than the proximal portion 58 or distalportion 60. For example, the intermediate portion 56 may be made of apolymer while the proximal portion 58 and distal portion 60 are madefrom a more rigid material, such as a steel, a nickel-titanium alloy, anelastomer, or a more rigid polymer. The intermediate portion 56 mayalternatively be comprised of: a coil of more rigid material; a seriesof spaced bands; provided with slits, grooves, notches, dimples, orother surface or body modifications that thin portions of the wall ofintermediate portion 56; or manufactured in a spiral configuration orwith a spiral ribbon forming the wall or with a spiral thinning of thewall as shown in FIGS. 11 a-11 c such that the immediate portion 56 hasthe ability to flex.

The intermediate portion 56 may be welded to, crimped, attached byadhesives, or manufactured from the same piece or kind of material asthe proximal portion 58 and distal portion 60. In one embodiment, theintermediate portion 56 is about 80 mm in length such that the desiredor predetermined curve provided in the device 38 is fully defined by theintermediate portion 56.

The distal tip 16, 20, 52, or 54 is provided with an embodiment thatallows directly or indirectly for easy puncturing through tough and/orfibrous septa. After passing through the septum, however, the ductileintermediate portion 56 is no longer supported by the introducer 32 andflexes. The flexing of the intermediate portion 56 moves the distal orpuncturing tip 16, 20, 52, or 54 out of alignment with the proximalportion 58 of needle 10, thereby rendering it atraumatic to the anatomicstructures directly aligned with the puncture location and initialpuncturing direction.

FIG. 12 is a side view of the distal portion of an embodiment of atransseptal puncture device 38 similar to FIGS. 10, 11 a-11 c whereinthe distal portion 60, not the intermediate portion 56, is manufacturedor formed from a material or in such a manner that the distal portion 60of device 38 is more likely to bend than the proximal portion 58.

FIG. 13 is a side view of the distal portion of an embodiment of atransseptal puncture device similar to FIG. 12 , wherein the distal tip60, not the intermediate portion 56, is manufactured or formed from amaterial such that it is more likely to bend than the proximal portion58. Distal portion 60 may be formed with a predetermined curvature orbias so as to assume a J bend. This embodiment may be manufactured in asimilar manner as a floppy guidewire with J-shape distal tip. Whenunsupported by the introducer 32, it assumes an atraumatic distal bend,thereby blocking the puncture edge from contacting other parts of thepatient's anatomy.

FIG. 14 shows an embodiment similar to that shown in FIG. 13 with themodification that the spiral flexible tip portion 60 has beensubstantially lengthened according to requirements of the medicalapplication in which device 38 is intended to be used.

FIG. 15 a is a side elevational view of the distal portion of anembodiment of a transseptal puncture device 38 similar to FIG. 12 ,wherein the distal tip portion 60 and some intermediate portion 56 ismanufactured or formed from a material such that it is more likely tobend than the proximal portion 58. The enlarged perspective view of FIG.15 b illustrates the spiral construction of distal portion 60 andintermediate portion 56 using a spirally wrapped ribbon 62, which isformed from a metal ribbon made of such as stainless steel or nitinolwith a width of 0.2 to 0.8 mm and 0.1 to 0.25 mm thick with a helicityof 10 to 20 wraps per cm. Such a constructed distal portion 60 andintermediate portion 56 is readily flexible to any displacementperpendicular to the longitudinal axis of needle 10, but issubstantially rigid to any longitudinal compression when needle 10 isconfined within dilator 42 or introducer 32.

A stylet 64 may be used in conjunction with the transseptal puncturedevice 38. The stylet 64 locks onto the proximal hub 30 of the needleassembly 38 and is composed of metal, polymer, composite, rubber,ceramic, or glass, though preferably from a stainless steel or nickeltitanium alloy.

The distal portion of the stylet 64 of FIG. 16 has an intermediateportion 56 some small predetermined distance, e.g. 1 to 10 mm, from thedistal tip 16, 20 where intermediate portion 56 is manufactured in anmanner or formed from a material that it is more likely to bend than theportions of the stylet 64 that are proximal or distal to theintermediate portion 56, similar to that described above. For example,the intermediate portion 56 may be necked down to a diameter ofapproximately 0.008″ relative to the proximal portion 58 with a diameterof approximately 0.018″ and distal portion 60 with a diameter ofapproximately 0.018″ such that less force is required to flex in theintermediate portion 56. Alternatively, geometric, material, orstructural modification may make the intermediate portion 56 moreflexible, for example, by the introduction of slits, grooves, cut-aways,notches, dimples, flats, ovals, taper, or other modification that thinsportions of the wall of the intermediate portion 56, which may or maynot have a coating or extrusion of softer material covering thestructural modification. The distal portion 60 or intermediate portion56 may be made from a softer material such as shape memory alloy (SMA)that forms a curve when exposed to body temperatures. The intermediateportion 56 may also be comprised of a hinge or coil designed to easilyand temporarily bend the stylet 64 off its longitudinal axis. The distalportion 60 may also be bent, curved, angled, or heat formed relative tothe proximal portion 58 such that even less force is required toinitiate the flex of the tip or the distal tip 16, 20 is less traumaticto body tissues than when it is straight. The end of the distal portion60 may have a smooth, rounded, sphere, spherical, ball-end, or radiusedtip to make the stylet even more atraumatic and prevent injury tocardiac tissue.

The operation of a stylet 64 and needle 78 is diagrammaticallyillustrated in FIG. 25 . The operation of an atrial transseptalprocedure can be seen to comprise four steps including: 1) a first stepof tenting the septal wall 11 with a stylet 64 in a middle extensionwith respect to the needle 78 in which it is disposed as illustrated inFIG. 17 a; 2) a second step in which the stylet 64 is pushed fully intothe needle 78 as illustrated in FIG. 17 b by the septum (11 FIG. 25 );3) a third step in which the needle 78 extends distally and penetratesseptal wall 11 as illustrated in FIG. 25 ; and 4) a fourth step in whichthe stylet 64 springs forward through the needle 78 to protect theneedle tip 86 from further penetration. FIG. 25 shows the curvedintroducer assembly 88 with bird's beak needle embodiment 10 pf FIG. 1 band stylet 64 in FIG. 17 . The dilator 88 and stylet 64 are used to tentthe septal wall 11. The sharp tip of the needle 78 then pierces theseptal wall 11 once the stylet 64 has completely pushed into the needle78, which allows the stylet 64 to spring forward into the left atrium 13and assume an atraumatic configuration or shape. The dilator 88 is thenable to advance over the needle 78 and stylet 64 into the left atrium13.

FIG. 26 depicts a blunt tip needle 52 with sharp stylet 65. In thisembodiment, the stylet 65 comprises a sharp tip that is used to puncturethe septal wall 11. The blunt tip needle 52 is used only to providecolumnar strength to the introducer assembly 88 and to aid in tentingthe septal wall 11. Once the septal wall 11 is tented, the stylet 65 isadvanced by the user, and the sharp tip punctures the septal wall 11.The stylet 65 then advances forward into the left atrium 13 and assumesan atraumatic configuration. The blunt tip needle 52 and dilator 88 maythen be advanced over the stylet 65 into the left atrium 13.

A spring-like mechanism 66 is attached to the proximal end of the stylet64 as shown in FIG. 16 . The spring-like mechanism may take the form ofone or a plurality of linear springs, torsional springs, gears,elastics, joints, pneumatics, buttons, or any other means of producingthe desired reactive forces. Various embodiments of spring mechanism 66are discussed below in connection with FIGS. 17-24 . The proximalportion 58 or stylet wire feeds into the spring-like mechanism 66 whilethe locking portion 68 connects to the needle hub 30 (not shown). Thespring-like mechanism 66 is formed from any spring or elastic materialthat acts in a way such that in its extended state it tends to return toits unextended or neutral length. The spring-like mechanism 66 ismanufactured from a spring metal, polymer, elastomer, rubber, a nickeltitanium alloy or superelastic material. It is comprised of one or aplurality of coils 92 and pistons 70.

One embodiment of spring mechanism 66 is shown in FIG. 18 wherein ahousing 90, forming part of hub assembly 30, includes a compressionspring 92 bearing against a piston 70, which is slidingly disposed intohousing 90 and to which stylet 64 is attached.

In one embodiment shown in FIG. 19 , the spring-like mechanism 66 andhub assembly 30 contains a slider 94 which is set into a slot 96 definedinto housing 90 and coupled to the spring 92 and/or stylet 64. Theslider 94 may move within the bounds of the slot 96 with the compressionand extension of the spring 92 as the stylet 64 moves through thepreviously discussed motions, or the slider 94 may be manually compelledto move along the slot 96 by the user. At the proximal and distal endsof the slot 96 are locking structures (not shown) which provide a meansto halt and temporarily hold the motion of the slider 94 at the extremesof its movement. For example, the slider and coupled stylet assembly maybe compelled to move to the most distal end of the slot 96 and join withthe locking structure, thereby temporarily fixing the slider's position.

When inserted into and locked onto the proximal hub 30 of the needle 10,the stylet tip 80 is useful to prevent skiving of the dilator 42 as theneedle 10 is advanced by extending from the needle tip by apredetermined amount, e.g. 1 to 10 mm, and guiding the needle tip awayfrom the inner wall of the dilator. When the needle 10 is positioned totent the septum, the distal end of the stylet 64 is pushed back into thehousing 90, thereby extending the spring-like mechanism 66 at theproximal end and exposing the needle tip 16, 20, enabling the needle tip16, 20 to puncture the septum. When the needle 10 punctures the septum,the stylet 64 springs forward through the puncture hole, allowing thestylet tip 80 and intermediate portion 56 to protrude from the needletip 16, 20 into the left atrium. Now unsupported by the needle 10, ordilator 42, the intermediate portion of the stylet 56 is able to flex,allowing the tip portion 82 to bend. This bent tip renders the stylet 64atraumatic and ensures that if the needle assembly 38 were to continueforward to contact the atrial free wall, then the bend in the tipportion 82 of stylet 64 prevents the needle tip 16, 20 from puncturingthe anatomy. Furthermore, the stylet proximal portion 58 may also extendpast the needle tip 16, 20 to ensure that the needle tip 16, 20 isadequately shielded from further puncturing.

In one embodiment, the spring-like mechanism 66 and hub assembly 30contains a lock or latch that clasps to the stylet lock 68. This ensuresthat the stylet tip 80 remains protruding from the needle tip until thelock or latch is released and maintains the atraumatic arrangement ofthe needle tip 16, 20 and stylet tip 80 while they reside in the leftatrium of the heart. A mechanism such as a cam 74 used in a ball pointpen allows the stylet 64 to lock and unlock.

FIG. 17 a depicts a stylet 64 of assembly 30 of FIG. 17 in a middleposition in relation to a needle 78. The stylet tip 80 extends the tipportion 82 of stylet 64 by a small amount, i.e. 1 to 4 mm, from thedistal end 86 of the needle 78 to reduce skiving of the distal end 86 onthe introducer assembly or dilator 88 (not shown in FIG. 17 a ). Thisstylet 64 comprises an intermediate portion 84, which has been neckeddown or ovalized for greater flexibility. As the intermediate portion 84remains supported by the needle 78, the stylet 64 maintains its columnarstrength.

FIG. 17 b depicts the stylet 64 in the fully retracted position inrelation to a needle 78. The stylet tip 80 does not extend at all fromthe distal end 86 of the needle 78. This may occur when the needle 78 istenting the septum, and therefore the septum exerts opposing force topush the stylet tip 80 into the needle 78. Alternatively, thespring-like mechanism 66 may contain a feature wherein the user is ableto pull back the stylet 64 so that it no longer protrudes from theneedle tip 86.

FIG. 17 c depicts the stylet 64 in the fully extended position inrelation to a needle 78. The stylet tip 80 extends out by a greateramount, i.e. 4 to 10 mm, from the needle tip 86. The intermediateportion 84 of the stylet 64 protrudes fully from the needle tip 86,allowing it to flex if necessary to prevent the needle tip 86 fromcontacting other anatomical structures.

In the embodiment shown in FIG. 20 , the stylet 64 starts in the middleposition of arcuate slot 100. Housing 90 includes a concentricallyincluded inner slidable housing 91 to which stylet 64 is indirectlycoupled. A pin 98 coupled to housing 90 rests in an arcuate slot 100initially near the etched or printed “X” 104 on housing 91, whichprovides a visual representation that the stylet 64 is positioned in themiddle, partially retracted configuration similar to FIG. 17 a . Duringtenting of the septum, the stylet 64 is pushed back, retracting the pin98 in arcuate slot 100 to a rearward position 106 and compressing thespring 70, which pushes the knob 102 away from the housing 90. As soonas the needle 78 (not shown in FIG. 20 ) punctures the septum, thespring 70 pushes the stylet 64 forward into its fully extended positionsimilar to that shown in FIG. 17 c . This motion also slides the knob102 and pin 98 forward in arcuate slot 100 to the position shown in FIG.20 . The angled wall 108 prevents the pin 98 from returning to the “X”side 104 of the slot 100, so the pin 98 and stylet 64 continue to slideto the most distal end of the slot 100. An audible snap can be heardwhen the spring 70 pushes the knob 102, pin 98, and stylet 64 to themost distal position. The pin 98 positioned near the etched or printed“0” 110 provides a visual representation that the stylet 64 is nowpositioned in the fully extended position similar to that shown in FIG.17 c . To reset the stylet 64 and pin 98 assembly to the middleposition, the user may pull the knob 102 away from the housing 90 toretract the stylet 64, rotate the knob 102 counter clockwise to push thepin 98 around the angled wall 108, and then release the knob 102 toallow the spring 70 to push the pin 98 into the “X” slot 104.

In another embodiment as shown in FIG. 21 , the movement of stylet 64 isdriven by an extension spring 70 and a full rotation slot 112, whichmeans that slot 112 extends fully around inner housing 91 and is definedonly partly into inner housing 91, which remains an integral orone-piece element. This allows knob 102 to be fully rotated by 360°returning in one turn to its initial position. In this embodiment spring70 is extended between the inner and outer housings 90 and 91 to producethe spring mechanism 66 more proximately relative to the patient insteadof more distally from the patient as in the embodiment of FIG. 20 . Thestylet 64 begins in the middle position divot 114. At this point, a pin118, which is connected to housing 90 and engages with a rotatingcylindrical housing 91 and knob 102, sits in a divot 114 of the arcuateslot 112. When the stylet 64 is pushed back during tenting, the spring70 begins to extend, pushing and rotating the cylindrical housing 91 tothe most proximal position 120 in the slot 112. This is the fullyretracted position. When the needle punctures the septum, the extensionspring 70 forcefully compresses, thereby extending and sending thestylet 64 forward to protrude fully from the tip of the needle (notshown). During this action, the cylindrical housing 91 moves distallyuntil pin 118 hits the most distal end 122 of the slot 112 with anaudible click. This noise serves as an auditory, visual, and tactilesignal that the stylet 64 has reached is maximal extension distance. Theknob 102 may then be rotated clockwise in relation to the cylindricalhousing 90 such that the coupled pin 118 follows the slot 112 back downinto the divot 114. This movement partially extends the spring 70 andretracts the stylet 64 back to the middle position.

In another embodiment shown in FIG. 22 , the movement is driven by acompression spring 70 and a partial rotation or arcuate slot 116. Thestylet 64 begins in the middle position 126. At this point, a pin 124,which is connected to housing 91, sits in a notch 126 of the arcuateslot 116. Housing 90 includes a concentric inner slidable housing 91, anintermediate concentric housing 93 in which slot 116 is defined andbearing against spring 70. Pin 124 is fixed to inner housing 91 and isdisposed in slot 116. When the stylet 64 is pushed back during tentingof the septal wall, the spring 70 begins to extend, which causes thecylinder 91 fixed to the pin 124 to rotate. The pin 124 slides down tothe most proximal end 130 of the slot 116 extending spring 70. When theneedle (not shown) punctures the septum, the spring 70 forcefullycompresses, thereby moving the stylet 64 into its fully extendedposition similar to FIG. 17 c . This motion pulls housing 93 down withthe spring 70 along with pin 124 in arcuate slot 116, which causes thecylinder 91 to rotate. The rotating cylinder 91 slides with pin 124along the length of arcuate slot 116. This rotational motion also causesthe screw 95 rotationally fixed to housing 90 and which is coupled to abutton 134 that protrudes from the distal end 136 of the housing 90 tomove linearly due to keyway 132. Screw 95 is freely threaded intohousing 91, and the coupled button 134 is keyed to housing 90 so that itmay slide in and out of housing 90, but may not rotate therein. It isalso within the scope of the invention that rotation of button 134 onscrew 95 is free so that frictional restraint of button 134 by itsmanual depression substantially prevents its rotation and thus causesscrew 95 to rotate as button 134 is depressed. The rotational motion ofthe screw 95 causes a linear motion that drives the button 134 toprotrude farther from the housing 90. To retract the spring 70, the usermay compress the button 134. The button 134 is coupled to the screw 95,which is driven forward and causes the cylinder 91 to rotate. Thecylinder rotation drives the pin 124 around the slot 116 towards theproximal end 138 of housing 90. The pin motion causes the slot 116 tomove distally, which extends the spring 70. The motion stops when thepin 124 reaches the notch 126, and the stylet 64 is therefore placedback in its middle position similar to that shown in FIG. 17 a.

In the embodiment of FIG. 23 an angled tooth cam 162 rotates with theknob 102. Outer housing 90 has a threaded end proximal to the patient.Inner housing 91 slidingly disposed within outer housing 90 has an endcap 93 threadably coupled to the proximal threaded end of outer housing90. End cap 93 is rotatable with outer housing 90 by means of manualrotation of knob 102. Spring 70 is captively retained within outer andinner housings 90 and 91, which are coupled together, and bears againstend cap 93. Spring 70 is coupled at one end to housing 91 and at itsopposing end to slider 166. The user holds the outer housing 90 and/orknob 102 and pushes and rotates pusher 168 with an arcuate slot (notshown) defined in outer housing 90 so that cam tooth 164 is rotatedrelative to cam body 162 and stylet 64 extended or withdrawn accordingto control of the cammed surfaces. As the cam body 162 rotates tooth 164rides up on the cammed surface and pushes slider 166 and stylet 64 towhich slider 166 is connected toward the patient. The cam body 162 maybe provided with a plurality of cam surfaces on which cam tooth 164rides so that the relative positions described in connection with FIGS.17 a-17 c can be configured. In the fully retracted position shown inFIG. 23 , stylet 64 is retracted within needle 78. When cam tooth 164rides up onto the cam surface of cam body 162, the septum will be tentedand penetration of the septal wall follows. Rotation of tooth 164 ontothe cam surface when cam body 162 is rotated with knob 102 ensures thatthe stylet tip 72 remains in its extended state until the lock or latch168 is released. This maintains the atraumatic configuration of theneedle tip 16, 20 and stylet tip 72 while in the left atrium of theheart. Extension spring 70 extends when stylet 64 is pushed back intohousing 90 in the fully retracted position. Relative rotation of knob102 with respect to pusher 168 thus controls the degree of compressionof spring 70.

In another embodiment shown in FIG. 24 , the movement is driven by twosprings, an extension spring 70 a, a compression spring 70 b and ahinged pin 130. The button 140 is coupled to compression spring 70 b anda hinged pin 130 which is rotatable about pivot 144. The pin 130 ispivoted where it is coupled to the button 140, while an arm 146 extendsthe distal end pin 130 for coupling with the complexly shaped slot 148defined in a slider 142, which is slidable (and alternatively rotatableas in FIG. 22 ) within housing 90. Arm 146 is axially positioned withinhousing 90, but longitudinally slidable therein. The proximal end 150 ofthe slider 142 relative to the patient is coupled to the stylet 64 andextension spring 70 a. Distal movement of slider 142 relative to thepatient thus draws stylet 64 back or away from the patient. Proximalmovement of slider 142 relative to the patient pushes stylet 64 towardthe patient. In an embodiment where slider 142 has a square crosssection shape at least one position and slides in a correspondingrectangular cavity defined by housing 90, pin 130 pivots or rotates asit rides in slot 148 on a face of slider 142. In another embodimentslider 142 is cylindrical with a round or circular cross section in acorresponding cylindrical cavity defined by housing 90, slider 142 andstylet 64 rotate as slider 142 moves toward or away from the patientout.

Prior to beginning the motion, the stylet 64 rests in its most proximalposition relative to the patient while the pin 130 is positioned in slot148 at its most distal position 160. In this position, the introducerassembly (not shown) is able to be inserted into the patient and tentthe septum. When the septum is tented, the stylet 64 is pushed back bythe septum into the needle (not shown) similar to that shown in FIG. 17b . This movement extends the extension spring 70 a and moves the slider142 distally from the patient, which causes the pin 130 to move into themost proximal point 158 of the slot 148. Once the needle 78 puncturesthe septum, the extension spring 70 a compresses forcefully, whichcauses the stylet 64 to spring proximally toward the patient and intothe left atrium. Slider 142 moves proximally toward the patient in thehousing 90, which is handheld in a fixed location. This movement causesthe slider 142 to move relative to the pin 130 such that the pin 130 isnow positioned at the intermediate portion 156 of the slot 148,compression spring 70 b is partially extended and button 140 is stillfully extended out of housing 90. To return the slider 142 to itsoriginal position, the button 140 is pressed into housing 90, thecompression spring 70 b shortens or compresses. This movement causes thepin 130 to move down the angled portion 152 of the slot 148. When thefully depressed button 140 is released by the user, the compressionspring 70 b expands and overcomes the force of extension spring 70 a. Asthe pin 130 can only move along the path of the slot 148 and along theedge 154, the pin 130 returns to the original position. The springmechanism 66 is now fully returned to its original position, and thetransseptal procedure may be reperformed with a subsequent button press.

Additional embodiments of the above mechanisms have also been conceivedthat facilitate the stylet 64 locking in an intermediate position sothat once the septum 11 (not shown) has been punctured by the needle,the stylet advances beyond the needle tip and locks in place, only to bere-set by pushing a button or rotating a knob on the proximal portion ofthe device (from the user perspective). This locking mechanism allowsthe stylet to have a more rigid distal portion or a lighter springwithin the mechanism as the locking will prevent the stylet frominadvertently pushed back into the needle and subsequently exposing thesharp needle tip. These embodiments also have the ability for the stylet64 to have an initial shorter projection from the needle tip whententing the septum, and a longer projection from the needle tip once theseptum has been crossed by the needle.

Many alterations and modifications may be made by those having ordinaryskill in the art without departing from the spirit and scope of theembodiments. Therefore, it must be understood that the illustratedembodiment has been set forth only for the purposes of example and thatit should not be taken as limiting the embodiments as defined by thefollowing embodiments and its various embodiments.

Therefore, it must be understood that the illustrated embodiment hasbeen set forth only for the purposes of example and that it should notbe taken as limiting the embodiments as defined by the following claims.For example, notwithstanding the fact that the elements of a claim areset forth below in a certain combination, it must be expresslyunderstood that the embodiments includes other combinations of fewer,more or different elements, which are disclosed in above even when notinitially claimed in such combinations. A teaching that two elements arecombined in a claimed combination is further to be understood as alsoallowing for a claimed combination in which the two elements are notcombined with each other, but may be used alone or combined in othercombinations. The excision of any disclosed element of the embodimentsis explicitly contemplated as within the scope of the embodiments.

The words used in this specification to describe the various embodimentsare to be understood not only in the sense of their commonly definedmeanings, but to include by special definition in this specificationstructure, material or acts beyond the scope of the commonly definedmeanings. Thus if an element can be understood in the context of thisspecification as including more than one meaning, then its use in aclaim must be understood as being generic to all possible meaningssupported by the specification and by the word itself.

The definitions of the words or elements of the following claims are,therefore, defined in this specification to include not only thecombination of elements which are literally set forth, but allequivalent structure, material or acts for performing substantially thesame function in substantially the same way to obtain substantially thesame result. In this sense it is therefore contemplated that anequivalent substitution of two or more elements may be made for any oneof the elements in the claims below or that a single element may besubstituted for two or more elements in a claim. Although elements maybe described above as acting in certain combinations and even initiallyclaimed as such, it is to be expressly understood that one or moreelements from a claimed combination can in some cases be excised fromthe combination and that the claimed combination may be directed to asubcombination or variation of a subcombination.

Insubstantial changes from the claimed subject matter as viewed by aperson with ordinary skill in the art, now known or later devised, areexpressly contemplated as being equivalently within the scope of theclaims. Therefore, obvious substitutions now or later known to one withordinary skill in the art are defined to be within the scope of thedefined elements.

The claims are thus to be understood to include what is specificallyillustrated and described above, what is conceptionally equivalent, whatcan be obviously substituted and also what essentially incorporates theessential idea of the embodiments.

We claim:
 1. A hollow needle assembly for a transseptal cardiac needlecomprising: a distal portion; a proximal portion; and a spring mechanismcoupled to the hollow needle assembly such that the spring mechanism isloaded when the hollow needle assembly is advanced against apredetermined position on a septal wall, and where the spring mechanismis unloaded after the transseptal cardiac needle penetrates the septalwall allowing the distal portion of the transseptal cardiac needle toextend unsupported and thereby assume an atraumatic configuration, wherethe distal portion of the transseptal cardiac needle is comprised ofmaterial that is more flexible relative to the proximal portion.
 2. Thehollow needle assembly for a transseptal cardiac needle of claim 1 wherethe distal portion of the transseptal cardiac needle comprises a spiralstructure providing it with increased flexibility as compared to theproximal portion.
 3. The hollow needle assembly for a transseptalcardiac needle of claim 2 where the distal portion of the transseptalcardiac needle includes a defining wall and where the spiral structurecomprises thinning the defining wall of the distal portion in a spiralpattern.
 4. The hollow needle assembly for a transseptal cardiac needleof claim 2 where the distal portion of the transseptal cardiac needle iscomprised of a spiral wrap.
 5. The hollow needle assembly for atransseptal cardiac needle of claim 4 where the distal portion of thetransseptal cardiac needle has a predetermined curve defined therein. 6.The hollow needle assembly for a transseptal cardiac needle of claim 1where the distal portion of the transseptal cardiac needle includes adefining wall and where the structure comprises thinning the definingwall of the distal portion.
 7. The hollow needle assembly for atransseptal cardiac needle of claim 1 where the distal portion of thetransseptal cardiac needle comprises an inherently flexible material. 8.The hollow needle assembly for a transseptal cardiac needle of claim 7where the inherently flexible material is nitinol.
 9. The hollow needleassembly for a transseptal cardiac needle of claim 1 further comprisinga stylet coupled to the spring mechanism such that the spring mechanismis loaded when the stylet is advanced against a predetermined positionon a septal wall, and where the spring mechanism is unloaded after thetransseptal cardiac needle penetrates the septal wall allowing thedistal portion of the transseptal cardiac needle to extend unsupportedand thereby assume an atraumatic configuration.
 10. The hollow needleassembly for a transseptal cardiac needle of claim 1 where thetransseptal cardiac needle comprises a bird beak tip, the bird beak tipcomprising: an inner surface; and an outer surface, where the bird beaktip has a longitudinal axis and a leading edge of the bird beak tip,where the leading edge of the bird beak tip is located at and adjacentto the distal end of the inner and outer surfaces, where the innersurface of the hollow transseptal cardiac needle defines an opening ofthe bird beak tip, and where the distal end of the bird beak tip iscurved relative to the longitudinal axis of the hollow transseptalcardiac needle into the opening of the bird beak tip.
 11. The hollowneedle assembly for a transseptal cardiac needle of claim 9 where thestylet comprises: a distal portion; and a proximal portion, where thedistal portion is comprised of material that is more flexible relativeto the proximal portion.
 12. The hollow needle assembly for atransseptal cardiac needle of claim 1 where the transseptal cardiacneedle comprises a tip, the tip comprising: an inner surface of theneedle; an outer surface of the needle, where the inner and outersurfaces of the needle have a common longitudinal axis; a bevel providedon a distal end of the needle to define a face of the needle; and a pairof opposing side bevels defined into a distal end of the face of theneedle, the side bevels intersecting at the distal end of the needle todefine the needle tip, where the distal end of the needle and the needletip bends toward the longitudinal axis of the needle.
 13. A method ofusing a spring mechanism coupled to an elongate stylet or needle for atransseptal cardiac procedure comprising: providing a stylet or needlecomprising a distal portion and a proximal portion, where the distalportion is flexible relative to the proximal portion; disposing thestylet or needle into an atrium in a heart oriented toward a selectedposition against a septal wall, the stylet or needle being coupled tothe spring mechanism; advancing the stylet or needle against theselected position on the septal wall while tenting the septal wall andwhile spring loading the spring mechanism; and automatically unloadingthe spring mechanism as the stylet or needle penetrates the septal wallallowing the stylet or needle to extend unsupported into an opposingatrium and to assume an atraumatic configuration.
 14. The method ofclaim 13 where providing the stylet or needle comprising a distalportion and a proximal portion comprises providing the distal portionwith a spiral structure.
 15. The method of claim 13 where providing thestylet or needle comprising a distal portion and a proximal portioncomprises providing the distal portion with a spiral wrap.
 16. Themethod of claim 14 where providing the distal portion with a spiralstructure comprises thinning a defining wall of the distal portion in aspiral pattern.
 17. The method of claim 13 where providing the stylet orneedle comprising a distal portion and a proximal portion comprisesproviding a distal portion that is comprised of an inherently flexiblematerial.
 18. The method of claim 17 where providing a distal portionthat is comprised of an inherently flexible material comprises a distalportion that is comprised of nitinol.
 19. The method of claim 13 furthercomprising locking the spring mechanism so that the stylet is fixed inposition relative to the needle and serves to atraumatically preventadvancement of the needle into heart tissue.
 20. The method of claim 13further comprising emitting a visual, audible, or tactile response fromthe spring mechanism to indicate when the stylet or needle is tentingthe septal wall and/or when the needle has perforated the septal wall.